My advice would be neither, the case comes with three large, decent quality fans which are likely to be sufficient for any project. Give them a go and see how you get on, it's relatively easy to change things later. Noctua would be a good brand to look at, most of their fans look kinda rubbish but they come with great documentation and performance.
When fans refer to "unrestricted" airflow, they don't usually mean things like mesh or dust filters as these are an incredibly common case feature these days. It really just means where you aren't trying to push air through a radiator, against a component or without a proper intake/exhaust.
Given that Corsair bundles the case with variants of the AF140, it seems pretty clear that they believe it's the best choice, and based on the data available, I'm inclined to agree.
I'm no fluid dynamics expert, but if a fan is capable of producing a pressure on one side, it would stand to reason that the other side produces a negative pressure that is roughly equal. I'm sure there's been a lot of research done on the subject, especially by people doing push-pull configurations on radiators.
Finally, it's really important to make sure you are comparing things fairly. Corsair's data for comparisons does not use fans set to a consistent speed or noise target. Across the board the AF fans run slower and quieter so even though they might produce similar CFM figures, they are doing it far more efficiently. In a real world scenario where you'd probably fiddle with fan speeds to make noise levels more liveable, this is hugely significant.
Sorry for the late reply.
I have heard great things about Noctua fans. I personally would rather buy something cheaper and more aesthetically pleasing, even if they sacrifice a small amount of performance.
So I should stick with the AF series.
Last question. Shouldn't 3 120mm fans push more air than 2 140mm?